ci: pin action refs to SHA + add dependabot.yml — §15

.github/dependabot.yml

@@ -0,0 +1,24 @@
+# TGWAB dependency updates—DEV-STANDARDS §15.
+#
+# Place at:  .github/dependabot.yml
+#
+# Grouping caps a normal week at ~3 PRs instead of one per package—ungrouped
+# Dependabot is how automated updates get muted and then ignored.
+
+version: 2
+
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+      time: "06:00"
+      timezone: America/New_York
+    open-pull-requests-limit: 2
+    labels: [dependencies]
+    commit-message:
+      prefix: "chore(actions)"
+    groups:
+      actions:
+        patterns: ["*"]

.github/workflows/backup.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: self-hosted
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
 
       - name: Ensure rclone present
         run: rclone version

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
   ci:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
       - name: Shell syntax across every tracked script
         # This repo is the estate's shell library; a syntax error here is only
         # found when someone runs the script on a live host.